Method of making tobacco sheet material



United States Patent O 3,499,454 METHOD OF MAKING TOBACCO SHEET MATERIAL John D. Hind, Richmond, Va., assignor to Philip Morris Incorporated, New York, N.Y., a corporation of Virginia No Drawing. Continuation-impart of application Ser. No. 606,527, Jan. 3, 1967. This application Dec. 7, 1967, Ser. No. 688,653

Int. Cl. A241) 9/00, 3/14, 13/00 US. Cl. 131140 1 Claim ABSTRACT OF THE DISCLOSURE This disclosure relates to a process for producing reconstituted tobacco sheets. The binder is made from tobacco plant parts and involves the use of the naturally occurring tobacco pectins, which are obtained by a process in which ammonium carbonate is employed to treat the tobacco plant parts. The treatment involves the destruction of the alkaline earth metal cross-links of the tobacco pectins, the release of the resulting tobacco pectins by a washing action and the depositing of the released tobacco pectins on the treated plant parts.

RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 606,527, which was filed on Jan. 3, 1967, now abandoned, and which is a continuation in part of application Ser. No. 557,903 which was filed on June 16, 1966 now Patent No. 3,353,541 and of application Ser. No. 636,537 which was filed on Apr. 24, 1967, now abandoned and which is a division of application Ser. No. 557,903, which issued on Nov. 21, 1967 as US. Patent No. 3,353,541 and which, in turn, is a continuation-in-part of application Ser. No. 336,009, which was filed on Jan. 6, 1964, now abandoned, which was a continuation-inpart of application Ser. No. 240,130 filed Nov. 26, 1962, now abandoned, and application Ser. No. 169,995 filed Ian. 16, 1962, now abandoned.

BACKGROUND OF THE INVENTION This invention relates, generally, to methods of producing tobacco sheet materials. More particularly, the invention relates to an improved method of making reconstituted tobacco compositions. In addition, the invention relates to methods for the production of novel adhesive compositions comprising tobacco pectins, to reconstituted tobacco containing tobacco pectins as binders.

During the production and processing of tobacco products, including aging, blending, sheet forming, cutting, drying, cooling, screening, shaping and packaging, considerable amounts of tobacco fines and tobacco dust are produced. It is known that such tobacco fines and dust can be combined with a binder to form a coherent sheet, which resembles leaf tobacco and which is commonly referred to as reconstituted tobacco. One method for making reconstituted tobacco of this general character is disclosed in United States Patent No. 2,734,510, wherein the tobacco fines and dust are applied to a binder made of carboxymethyl cellulose, carboxymethyl hydroxethyl cellulose or a suitable salt thereof. The binder, in such compositions, ranges from about 5% to about 50% of the weight of the tobacco employed. United States Patent No. 2,708,175, describes a binder for reconstituted tobacco which consists of a plant gum, principally of galactomannan. United States Patent 2,592,554 to Frankenburg describes, as binders for reconstituted tobacco, various water-soluble polysaccharides, such as alginic and pectinic acids and their sodium and potassium salts, derived from plants other than tobacco; for example derived from 3,499,454 Patented Mar. 10, 1970 citrus fruits. However, the addition of cellulosic binders further increases the amount of cellulosic material in the product and tends to create and acrid and bitter smoke, when the product is used to make cigarettes. The natural hydrophilic celloid gurns such as guar gum, locust bean gum, algin and other commonly used materials, such as Irish moss, have additional disadvantages. These materials contain proteins and other materials not found in tobacco which add distinctive flavors of their own to tobacco products during smoking. Thus, Frankenburg, in describing the use of various water-soluble polysaccharides derived from plants other than tobacco, teaches that care should be exercised that they must be in a state of refinement. Frankenburg teaches that these materials should be free of extraneous matter containing compounds of nitrogen, particularly proteins, and compounds of sulfur, phosphorus and the halogens; i.e., compounds giving undesirable products of combustion or dry distillation. Such refining is often a very tedious and difficult operation.

The present invention makes possible the production of improved reconstituted tobacco by a method which is simpler and more effective than the methods previously employed. The present method does not require refining of the binder and is, therefore, more easily and efiiciently employed than other methods for making binders and for making reconstituted tobacco. The reconstituted tobacco which is obtained in accordance with the present invention need not contain any additional cellulose or proteinoceous material which is foreign to tobacco, since the binder which is employed may be derived solely from tobacco, and may be produced in such a manner that it contains no materials other than those which naturally occur in tobacco. Thus, reconstituted tobacco produced in accordance with the invention, can be so formulated as to be similar in physical properties and chemical composition to natural tobacco.

The term pectic substances means those substances which are found in many plant products, and which consist essentially of partially methylated galacturonic acids joined in long chains. Unless otherwise specified, the term pectins will, for convenience, hereinafter be employed interchangeably with the term pectic substances.

The pectic substances found in tobacco plants contain acetyl groups and difier considerably from commercially available pectins found in other plants, including sugar beet pectins and citrus and fruit pectins. Tobacco protopectins are uniquely insoluble in hot water as compared with protopectins from many other sources and comprise mainly water-insoluble pectins (protopectins) consisting of the calcium and magnesium salts of partially esterified and slightly acetylated polymers of galacturonic acid. The divalent calcium and/or magnesium atoms act as crosslinks between acids chains, thus making the polymers water-insoluble.

Although pectins have long been known as constituents of plant tissue, it has been found extremely difficult to separate pectins from the remainder of plant compositions and to obtain them as homogeneous compositions. The recovery of pectins from tobacco is even more difficult than the recovery of pectins from other plants.

THE INVENTION AND ITS EMBODIMENTS In accordance with the present invention, tobacco parts are bonded together by tobacco pectins which are specially prepared by a novel process which yields these pectins in a form in which they can be employed as binder materials. My process for preparing tobacco pectins comprises first reacting tobacco parts, preferably in a form in which they present a large surface area, with an aqueous solution of non-toxic reagent which is capable of reacting with and destroying the calcium and magnesium cross-links in the pectinaceous substances which naturally occur in tobacco. After the calcium and magnesium cross-links are destroyed, the tobacco pectins are liberated and made available for use as a binder. The tobacco pectins are then dissolved or dispersed in solution, or are at least sufficiently released from the interstices of the tobacco mass so that they form a coating on the surface thereof. Tobacco pectins which are dissolved or dispersed in the treating solutions, are thereafter precipitated or deposited from the solution, so that they become available for use as a binder material. In this way, the tobacco parts can be bonded together by a binder material which is made of ingredients that are closely related to the naturally occurring ingredients of tobacco. The bonding can be accomplished without the need for the purification of the tobacco pectins, inasmuch as any materials which are present are closely related to the materials which are normally present in tobacco and, thus, do not add any undesired qualities to the tobacco.

The tobacco parts which can be employed in the present invention include tobacco leaves, stems and stalks, or a mixture of these, whether in sheet, flake, particulate or other form. Preferably, the parts are ground, out or otherwise prepared in a form which presents a large surface area. The portions of the plant comprising the stems or midribs, and often referred to as tobacco petioles, are the preferred starting materials. Tobacco stalks contain lesser amounts of pectinaceous materials but can also be employed.

In the first step of the process of my invention, tobacco pectins are liberated from pectinaceous materials in tobacco by reacting the pectinaceous materials with a reagent which may, for convenience, be hereinafter referred to as a cross-link destroying reagent. This re agent, under the conditions of the reaction, is reactive with the calcium (and/ or magnesium) contained in them to form a compound or product having a lower calcium ion, and, in the case of magnesium, magnesium ion, concentration in the treating solution than the naturally occurring calcium (or magnesium) pectate.

The reaction may be generally represented by Equation I, which illustrates the reaction of one type of tobacco protopectin (a calcium salt of a polymer of galacturonic acid), wherein calcium cross-links are present with the reagent of the present invention. In the equation, R may be hydrogen, in which case the product is pectic acid, or R may be a monovalent inorganic cation, such as sodium, potassium or ammonium, in which case the product is a soluble pectate.

cross-link C OOCaf l f OHQOOO OH -OH HC--0--C-H HCO ZR C-O A g Treating reagent H H COO CH of this invention CALCIUM PECTATE PECTIC ACID 0R SOLUBLE PECTATE In the present embodiment of this invention, the re- 1 By concentration we mean concentration or activity as set forth in Glasstone, Textbook of Physical Chemistry, 2nd edition, page 954, D. V. Nostrand Company, Inc.

agent is ammonium carbonate and is preferably employed in aqueous solution. The conditions of temperature, concentration and the like will be set forth in greater detail below.

The pectin which results from the first step of this invention is in condition for release from the tobacco cell structure, R in Equation I being the monovalent inorganic cation ammonium.

Once the tobacco pectins have been liberated from the tobacco, by the removal of the calcium and magnesium cross-links, they should be released from the interstices of the tobacco. That is, they will be made available to the solution or supension or, in certain instances, they will be merely deposited on the surface of the tobacco particles. This comprises the second step of the process of the present invention. This release or second step may be accomplished concurrently with the first step by releasing the pectins with the solution of the treating reagent. Additional treating liquid or water may be used to effect the release through a washing action of the treated tobacco particles.

In accordance with the third step of my process, the liberated and separated tobacco pectins can next be precipitated or deposited in a relatively free form (as compared with the tobacco pectins as they were originally present in the tobacco), from the treating solution.

The tobacco pectins can, if desired, be recovered by concentrating the solution or suspension in which they are present until they precipitate. This precipitate might also be characterized as an intractable mass, since the pectin solution, upon concentration, generally becomes progressively more viscous until it finally dries to leave a deposit in a glassy solid state.

While the tobacco pectins can be separated and purified before use as a binder in reconstituted tobacco sheets, they are preferably employed just as they are produced in situ, i.e., in combination with the treated tobacco plant parts from which they were obtained, the entire combination comprising the binder for reconstituted tobacco sheets or, under some circumstances, the entire combination comprising essentially the entire components of a reconstituted tobacco sheet. By using the entire mixture, no original tobacco flavors are lost, all of the tobacco is employed, and no expensive and time-consuming refining operations are required.

Although it is not necessary, the thixotropic properties of solutions containing soluble pectins can be adjusted in the preparation of a cured sheet by the addition of such materials as calcium chloride. If any complex or precipitate form in the first step of this process is present with the soluble pectates, the thixotropic properties of the mixture can also be adjusted by adjusting the pH to precipitate calcium and magnesium pectates.

A preliminary step which may be employed in accordance with the present invention comprises washing the tobacco plant parts, which are preferably ground or cut to a relatively small size, With cold water. This water wash serves to remove impurities which might otherwise hinder the subsequent treatments in accordance with the present invention.

As generally discussed above, the present invention involves the use of ammonium carbonate for the release of the tobacco pectins. 'Ihe ammonium carbonate will, generally, be added to the tobacco plant parts, which may, for example, be bright tobacco parts, burley tobacco parts, or a mixture of the same, in an aqueous solution. The concentration of the ammonium carbonate in the aqueous solution is not critical, but will, generally, be in the range of 0.5-5.0% by weight. The ammonium carbonate and water may be added separate- 1y to the tobacco. The amount of ammonium carbonate should, preferably, comprise from about 0.01 to about 0.5 part, and, most preferably, from about 0.02 to 0.30 part (by Weight) per part of tobacco being contacted. A humectant, such as glycerin or triethylene glycol, may

be present, if desired. The temperature during the ammonium carbonate treatment of the tobacco may vary between room temperature and about 95 C. or higher at atmospheric pressure, depending on the type of tobacco being treated, but it will generally be found preferable to maintain a temperature of from about 6 5 to about 100 C. The pressure of the reaction may be atmospheric or may be higher or lower than atmospheric pressure and may be as high as 23 p.s.i.g., under which circumstance the temperature may be as high as 130 C. Preferably, a slight positive pressure, of the order of 5 to 10 p.s.i.g., is employed.

The pH of the mixture should preferably be maintained at a value of from about 7.0 to about 10.0, and preferably at a value of from 8.0 to 9.5. The pH may conveniently be maintained by the addition to the solution of concentrated aqueous ammonia. By agitating or stirring such a mixture under the above-described conditions for from about 1 minute to about 1 day, and, preferably, from about 1 hour to about 5 hours, the

tobacco pectins are liberated, released and deposited in p the tobacco plant parts to form a binder composition. The resulting mixture may then be refined, for example, in a disk refiner, until substantially all the pulp (in excess of the water present), can be shaken through a screen of approximately 18 mesh to produce a binder composition which is ready for use in the manufacture of reconstituted tobacco sheets.

Ammonium carbonate is particularly advantageous in the present process, since it imparts little or no residues to the tobacco product and, therefore, it does not slow down the burning rate of the tobacco, as can occur with other materials employed in a similar manner.

The term tobacco pectins as used throughout this specification means liberated tobacco pectins and comprehends pectins which have been freed or liberated from tobacco and are, therefore, not bound into the tobacco structure, as differentiated from the insoluble, naturally ocurring protopectins which are bound into a plant cell structure. The term includes the free pectinic or pectic acid, as Well as soluble salts such as the sodium, potassium, ammonium, pectates and pectinates, and insoluble salts such as the calcium and magnesium pectates and pectinates depending on what method is employed to liberate and obtain them from the naturally occurring insoluble protopectins.

The tobacco pectins produced or liberated in situ or isolated by means of this invention can be used as the sole binder material for reconstituted tobacco, i.e., no other materials need be added to make the sheet. They can be sprayed, extruded or cast, thus facilitating application onto a moving belt carrying tobacco dust. Under proper conditions of formulation and processing, reconstituted tobacco made with the tobacco pectins produced by this invention exhibit excellent physical and aromatic properties. The ultimate tensile and wet strengths of the reconstituted tobacco are good. While no other materials need be added to the pectinaceous binder, other materials can be added, if desired. For example, organic acids and preservatives which may in themselves be of tobacco origin, may be added. Plasticizers, such glycols and polyglycols, and humectants, such as glycerin, may also be added, if desired. In addition, the gel strength of the tobacco pectins can be regulated by partial precipitation to control such rheological properties as viscosity, fluidity and elasticity. Other additives or dispersants may be added in small amounts to regulate slurrying qualities, provided, however, that such substances are not added in large enough quantities to adversely affect the flavor or aroma of the final product. Furthermore, the tobacco pectins can be combined with water-soluble gums or water-dispersible gums commonly used as binders for tobacco sheets such as methyl cellulose, sodium carboxymethyl cellulose, guar gum, locust bean gum, or alginates,

although it is preferred to minimize or eliminate such additions in order to obtain a product which most closely resembles natural tobacco.

The product from treating the tobacco plant parts in accordance with the methods of the present invention may be cast directly and dried and cut into particulate material similar in physical form to ordinary smoking tobacco and so used, preferably mixed with tobacco leaf cut or shreadded in the usual manner. The product may be cast in sheet form, in blocks or as threads or other shapes, as desired. An important use, however, of the prepared composite slurry or easily molded isolated pectinaceous mass is as a binder for ground tobacco and for the making of corresponding tobacco products suitable for smoking. Sheet material of widely different properties may be formed by suitable variations in the manner of forming. One method and product comprises flowing the composite slurry onto a moving belt and applying a layer of dry ground of fragmented tobacco to the wet adhesive surface. If desired, there may be first applied to the belt a layer of the tobacco, followed by a layer of the binder, and then a top layer of the tobacco. Various additives may be included with the ground tobacco such as flavorants, plasticizers and aromatic substances. The web is ultimately dried and then suitably moistened and rolled up. Such methods of forming continuous sheets are known generally in the art and the details need not be further described. Representative of this procedure is the apparatus and method disclosed in US. Patent 2,734,513.

Another method of forming a reconstituted tobacco product, with the slurry of the isolated tobacco pectins as a binder, comprises mixing ground tobacco thoroughly therewith into a mass of dough-like consistency and then casting the mass in sheet form onto a moving belt surface followed by drying and remoistening in accordance with the known procedures. Representative of this procedure is the apparatus and method disclosed in US. Patents 2,708,175 and 2,769,734. Obviously, the reconstituted tobacco may also be formed by molding or other suitable means.

A particularly preferred aspect of the present invention comprises employing, as a binder or directly, the mixture of tobacco and tobacco pectins which have been produced in situ, without any separation steps and without the necessity for any additional adhesive materials.

The following examples are illustrative:

Example 1 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 4.0 g. of ammonium canbonate and 500 ml. of water. This amount of ammonium carbonate represented a 25% excess of the amount calculated to be necessary to react with the calcium and magnesium present in the tobacco being treated. The pH of the slurry was adjusted to a value above 8, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated on a steam bath for 2%. hours at a temperature of to C. The pressure within the jar was maintained at about 20 p.s.i.a. The slurry was then transferred into a Waring Blendor and 250 ml. of hot water was added, and the resulting mixture was stirred for 20 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet had good color.

The sheet was allowed to equilibrate to room conditions, with a controlled humidity of 60%. The wet tensile coefficient and sheet weight were determined. These results are tabulated below:

Moisture percent 12.6 Weight/ft. g./ft. 7.5 Wet tensile coefiicient 1 g./in./g./ft. 1.28

Wet tensile coefficient is the value of the wet tensile strength, in grams, per inch, divided by the weight of the sheet in grams per foot square. The wet tensile strength is determined as follows: Strips approximately 3 inches long and exactly 1 inch wide are cut from the sheets to be tested. They are individually placed between jaws of :1 Scott 'lensilograph recording tester and wet through in a line approximately inch wide across the direction of the testing with a few drops of water. After allowing 30 seconds for complete penetration of water, the tester is started, automatically recording the breaking strength in grams. The Scott Tensilograph is provided with carriages of various weights for recording tests in the ranges from O-50 grams up to -2 kilograms.

Experimental Sheet, percent Control Dust, percent Ash 18. 0 Ammonia--- Less than 0.01

Example 2 A slurry was prepared with 50 g. of unwashed tobacco dust (about 50 mesh), g. of ammonium carbonate, and 500 ml. of water. The pH was adjusted to a value of about 8.5 by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated on a steam bath for 3 hours at a temperature of 65 C. The pressure within the jar was maintained at about p.s.i.a. The slurry was then transferred into a Waring Blendor and 200 ml. of hot water was added, and the resulting mixture was stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade. During drying bubbles appeared on the surface, which resulted in cracks in the sheet.

The sheet was allowed to equilibrate to room conditions, with a controlled humidity of 60%. The wet tensile coefficient and sheet weight were determined. These results are tabulated below:

Sheet weight g.ft. 8.44 Wet tensile coefficient g./in./g./ft. 4.57

Example 3 A slurry was prepared with 50 g. of unwashed tobacco dust (about 50 mesh), 5.0 g. of ammonium carbonate and 500 ml. water. The pH of the slurry was adjusted to a value of 9.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, loosely sealed, and heated on a steam bath for 6 hours at ambient pressure, at a temperature of 90 C. The slurry was then transferred into a Waring Blendor and stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 9.2. The mixture was then deaerated for 20 minutes by the application of a vacuum, while the mixture was maintained at a temperature of about 90 C., and the mixture was then cast on a steel plate to form a sheet approximately 50 mils thick (wet thickness) using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet had a good appearance, with little or no cracks.

I'll

Example 4 A slurry was prepared with 50 g. of unwashed tobacco dust (about 50 mesh), 4.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar and heated on a steam bath for 3 /2 hours at room pressure and at a temperature of C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 85 C. The pH of the resultingv mixture was found to be about 8.5. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting sheet appeared very good.

The sheet was allowed to equilibrate to room conditions, with a controlled humidity of 60%. The wet tensile coefficient and sheet weight were determined. These results are tabulated below:

Weight/ft? g./ft. 12.26 Wet tensile coefficient g./in./g./ft. 2.06

Example 5 A slurry was prepared with 30 g. of unwashed tobacco dust (about 50 mesh), 3.0 g. of ammonium carbonate and 300 ml. water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was then transferred into a Waring Blendor and was stirred for 2 hours, while maintained at a temperature of about C. The pH of the resulting mixture was found to be about 8.8. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was satisfactory.

Example 6 A slurry was prepared with 50 g. of unwashed tobacco dust, 1.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar and heated on a steam bath for 3 hours at a temperature of about 85 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then deaerated for 20 minutes and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 7 A slurry was prepared with 50 g. of unwashed tobacco dust, 2.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar and heated on a steam bath for 3 /2 hours at a temperature of about 85 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then deaerated for 20 minutes and cst on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 8 A slurry was prepared with 50 g. of unwashed tobacco dust, 5.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar and heated on a steam bath for 3 /2 hours at a temperature of about 85 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then deaerated for 20 minutes and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of adoctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 9 A slurry was prepared with 50 g, of unwashed tobacco dust, 15.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar and heated on a steam bath for 3 /2 hours at a temperature of about 85 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 90 C. The pH of the resulting mixture was found to be about 8.5. The mixture was then deaerated for 20 minutes and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 10 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 5.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated on a steam bath for 3 /2 hours at a temperature of about 65 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 85 C. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mills thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 11 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 5.0 g. of ammonium carbonate and 500 ml. of Water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated on a steam bath for 3 /2 hours at a temperature of about 75 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about 90 C. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 12 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 5.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding a concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated on a steam bath for 3%. hours at a temperature of about 95 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about C. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

' Example 13 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 5.0 g. of ammonium carbonate and 500 ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of about 100 C. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about C. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 14 A slurry was prepared with 50 g. of unwashed bright tobacco dust, 5.0 g. of ammonium carbonate and 500ml. of water. The pH of the slurry was adjusted to a value of 9.0, by adding a concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 /2 hours at a temperature of about 114 C. The pressure within the jar was maintained at about 25 p.s.i.a. The slurry was then transferred into a Waring Blendor and was stirred for 15 minutes while maintained at a temperature of about C. The mixture was then deaerated and cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 15 A slurry was prepared with 45 g. of unwashed tobacco dust, 2.5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 8.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.a. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 8.3. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

1 1 Example 16 A slurry was prepared with 45 g. of unwashed tobacco dust, 3.38 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 8.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.a. The slurry was then transferred into a Waring Blendor and stirred for minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 8.6. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 17 A slurry was prepared with 45 g. of unwashed tobacco dust, 5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 8.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.a. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 8.8. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 18 A slurry was prepared with 45 g. of unwashed tobacco dust, 5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 8.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 115 C. The pressure within the jar was maintained at 10 p.s.i.g. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 8.3. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 19 A slurry was prepared with 45 g. of unwashed tobacco dust, 5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 9.5, by adding concentrated am-mounium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.g. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 9.3. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 20 A slurry was prepared with 4.5 g. of unwashed tobacco dust, 6.75 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 9.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.g. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about C. The pH of the resulting mixture was found to be 9.4. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to he the best sheet.

Example 21 A slurry was prepared with 45 g. of unwashed tobacco dust (about 40 mesh), 5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 9.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.g. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintained at a temperature of about 95 C. The pH of the resulting mixture was found to be 9.0. The mixture was then cast on a steel plate to form a sheet approximately 50 mils thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

Example 22 A slurry was prepared with 45 g. of unwashed tobacco dust (about 8 to +20 mesh), 5 g. of ammonium carbonate and 555 ml. of water. The pH of the slurry was adjusted to a value of 9.5, by adding concentrated ammonium hydroxide to the slurry. The resulting slurry was placed in a jar, sealed, and heated for 3 hours at a temperature of 108 C. The pressure within the jar was maintained at 5 p.s.i.g. The slurry was then transferred into a Waring Blendor and was stirred for 10 minutes while maintaining at a temperature of about 95 C. The pH of the resulting mixture was found to be 9.0. The mixture was then cast on a steel plate to form a sheet approximately 50 mls. thick using an angle knife. The sheet was then dried by placing the plate on a steam bath, and the sheet was removed from the steel plate by means of a doctor blade.

The resulting reconstituted tobacco sheet was found to be satisfactory.

-I claim:

1. A process for producing a binder composition from tobacco plant parts containing pectins having alkaline earth metal cross-links which comprises the steps of:

(l) contacting said tobacco plant parts with a treating solution containing a reagent comprising ammonium carbonate to destroy the alkaline earth metal crosslinks;

(2) at least partially releasing the resulting tobacco pectins from the interstices of the treated tobacco plant parts;

13 14 (3) depositing said tobacco pectins on the treated 3,120,233 2/1964 Battista et a1 131-140 plant par-ts;and 3,353,541 11/1967 Hind et a1. 131-17 (4) recovering the ires-ulting mixture.

MELVIN D. REIN, Primary Examiner 5 US. Cl. X.R.

References Cited UNITED STATES PATENTS 3,012,915 12/1961 Howard 131-17 3,121,433 2/1964- Plunket-t et a1 131-140 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,499,454 March 10 1970 John D. Hind It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 62, "hydroxethyl" should read hydroxyethyl Column 2, line 3, "and", second occurrence, should read an line 53, "acids" should read acid Column 5, line 9, "23" should read 25 line 61, "such glycols" should read such as glycols Column 6, line 9, "shreadded" should read shredded Column 8, line 73, "cst" should read cast Column 9, line 20 "adoctor" should read a doctor Column 10, line 65, and Column 11, lines 9 and 28, "p.s.i.a.", each occurrence, should read p.s.i.g. Column 12, line 5, "4.5" should read 45 line 55, "maintaining" should read maintained line 58, "mls." should read mils Signed and sealed this 8th day of December 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

